1. Technical Field
The present disclosure relates to an image formation apparatus.
2. Description of the Related Art
As an image formation apparatus such as a printer, a facsimile machine, a copying machine, a printer/fax/copier composite machine, an ink jet recording apparatus is known for performing image formation (recording, printing, and imaging are used as the same meaning.) by making a liquid drop of recording liquid (also referred to as an ink drop, below) adhere to a paper using a recording head (image formation part) composed of a liquid discharging head for discharging the liquid drop of recording liquid, while a recording medium to be recorded (a paper, a recording medium, a transcribing medium, etc., are used as the same meaning.) is carried.
Thus, in the ink jet recording apparatus, since an image is formed using recording liquid and a certain amount of time is required until the recording liquid applied on a recording medium to be recorded is dried, while the recording liquid applied on the recording medium to be recorded is dried, the recording medium to be recorded on which the image formation has been completed is made be on standby inside the apparatus or, when double-sided printing is performed, after the recording medium to be recorded is once ejected onto an ejected paper tray, paper refeeding is performed.
For example, there is a description of having a part for delaying the ejection of a current recording paper onto an ejected paper tray by a set time when the result of judgment for a previous dot density is over a predetermined set value, in Japanese Patent No. 3109529.
Also, when double-sided printing is performed, after imaging is performed on one side of a paper, at least one portion of the paper is once ejected out of an apparatus body so that drying time can be kept, in Japanese Laid-Open Patent Application No. 2000-001010.
Meanwhile, recording liquid with a high viscosity (highly viscous ink) tends to be used in an ink jet apparatus in order to realize high speed and high quality image recording to a normal paper. That is, in ink jet recording, particularly when printing is applied on a normal paper, an image quality degradation problem that is specific to ink jet recording, on color reproducibility, durability, light resistance, ink drying property, character running (feathering), color border bleeding (color bleed), etc., of an image, is made be apparent, and when high speed printing is performed on a normal paper, it has been a very difficult problem to perform printing while all of these characteristics are satisfied.
Also, recording liquid (ink) used for ink jet recording is commonly based on water and generally contains a wetting agent such as glycerin for the purpose of the prevention of clogging, etc. As a coloring agent, there are provided a dye and a pigment, but, conventionally, dye-containing ink has been frequently employed in a color part since excellent chromophoric property or stability can be obtained. However, the fastness properties, such as light resistance and water resistance, of an image obtained using the dye-containing ink is inferior to the case of using a pigment as a coloring agent, and particularly, with respect to the water resistance, if a recording paper for the exclusive use of ink jet which has an ink absorbing layer is used, a certain degree of improvement can be provided, but if a normal paper is used, satisfaction has not been obtained.
Consequently, the use of pigment-containing ink in which an organic pigment, carbon black, etc., is used as a coloring agent has been investigated or the ink has been put to practical use, for printing on a normal paper, in order to solve the problem on the dye-containing ink in the case of using the normal paper. Since a pigment does not have solubility to water differently from a dye, a pigment is commonly mixed with a dispersing agent so as to be used as water-based ink on the condition that the pigment is stably dispersed by the dispersion treatment.
Since such pigment-based ink is generally highly viscous ink (5 mPa s or greater), the ink has a quick-drying property compared to the dye-containing ink in the case of printing on a normal paper, but there is a problem that curl of a recording medium to be recorded easily occurs.
That is, since free water of the dye-containing ink penetrates to the back face of a recording medium to be recorded so that the difference between water contents on the front and back faces of the recording medium to be recorded is reduced, the curl originating from the difference between the water contents on the front and back faces of the recording medium to be recorded is relatively difficult to occur although it takes a long time to dry.
On the other hand, since the pigment-based ink has a quick-drying property, it does not take so much time for the ink to dry on a recording medium to be recorded, and, however, since it takes a long time to penetrate into the recording medium to be recorded and the difference between water contents on the front and back faces of the recording medium to be recorded becomes large, the curl originating from the difference between the water contents on the front and back faces of the recording medium to be recorded easily occurs, and when the curl occurs, the ink solidifies on the condition of leaving the curl due to the quick-drying property.
Thus, when a paper on which the curl occurs is carried as it stands, there is a problem that a jam occurs, or the stability of paper ejection deteriorates so that folding, etc., occurs and the quality of a print degrades.